Previously many alternative types of systems have been introduced in endeavoring to improve and provide an efficient and practical Stirling cycle engine. Since its conception, in the early nineteenth century, a displacer and output power piston was operated in the same cylinder. More recently, some have attempted to use rotary mechanisming which have by their very nature reduced extraneous volume not swept by the pistons thereby enhancing compression resulting in efficiency beyond those of the early days. However, the present internal combustion engine has still far surpassed the efficiencies of the not only original concept developed by Stirling but even the latest improvements by others.
The use of rotors instead of pistons is just now becoming a practical reality due to the exhaustive development of rotary engines for automotive applications and fluid pumps. The need still exists however for the utilization of a system that will yield efficiencies duplicating or exceeding the latest piston engine technology.
A search of the prior art did not disclose any patents that read directly on the clams of the instant invention however, the following U.S. patents were considered related:
______________________________________ U.S. PAT. NO. INVENTOR ISSUED ______________________________________ 4,753,073 Chandler 28 June 1988 4,179,890 Hanson 25 December 1979 4,044,559 Kelly 30 August 1977 3,984,981 Redshaw 12 October 1976 3,958,422 Kelly 25 May 1976 3,537,256 Kelly 3 November 1970 3,370,418 Kelly 27 February 1968 ______________________________________
Chandler in U.S. Pat. No. 4,753,073, improved the Stirling cycle using three rotors each separately rotatable within a toroiadal housing cavity. Each rotor contains a pair of rotor blocks forming six separate chambers. Heat exchangers are employed and relative angular rotor movement within the chambers is achieved by meshing elliptical gears connected to a common output shaft.
Hanson teaches in U.S. Pat. No. 4,179,890 an epitrochoidal Stirling type engine using a three-lobed rotary piston in a four-lobed housing. A cam is coaxially mounted between rollers in sufficient preciseness to eliminate peripheral seals. Connectors for fluid flow between pairs of lobes permit the cycle to receive heat on one end and discharge it from the other.
U.S. Pat. No. 4,044,559 issued to Kelly discloses a closed series cycle or double-acting reciprocating Stirling engine cycle. Tandem rotary units employ a series gas flow loop using a large number of heat transfer tubes with separation between the hot and cold sources. Hydrogen gas is used as fuel obtained from an electrolysis unit driven by a wind generator.
Redshaw employs a rotary Stirling cycle system in U.S. Pat. No. 3,984,981 utilizing rotors also internal heat exchangers, and displacers as heat regenerators. Chambers are formed with two wedge-shaped spherical sectors connected by a disk-like coupling producing four variable displacement chambers. Sectors contain passageways through hollow shafts covered with fins to provide heat transfer porous heat absorbing material becomes the heat regenerator transferring heat from one chamber to the other.
U.S. Pat. No. 3,958,422 also issued to Kelly uses multiple rotary units having an eccentric rotor with vanes independent from adjacent units. Multiple heat transfer loops with heating and cooling sources provide the regeneration heat transfer. Hydrogen is employed as the working gas with any suitable fuel used as the heat source.
Kelly in an earlier patent (U.S. Pat. No. 3,537,256) uses two simple eccentric rotors with vanes and interconnecting flow paths. A modular split housing allows valves to be connected to both rotors. The heat is optically transmitted to a hot displacer. Photo heat powered by liquid fuel or electrical lamps provides the heat source for the invention.
Finally, Kelly in U.S. Pat. No. 3,370,418 issued a few year earlier disclosed a pressurized Stirling cycle engine employing both axial and radial gas flow. Two in-line cylinders are used, each having a truncated rotor and multiple rings on the rotor having impeller blades. A shaft supports the rotor and endplates with bearings support the shaft. A number of ports freely communicate with the cylinders allowing heat transfer and a circular regenerator provides internal counter-balancing.